title: Expression of the cannabinoid receptor type 1 in the pituitary of rabbits and its role in the control of LH secretion.
abstract: The aim of this study was to elucidate the possible direct regulatory role of the endocannabinoids in the modulation of LH secretion in rabbits, a reflex ovulator species. The cannabinoid receptor type 1 (CB1) was characterized by RT-PCR techniques in the anterior pituitary of intact and ovariectomized does treated with GnRH and primed with estrogen and CB1 antagonist, rimonabant. Cannabinoid receptor type 1 immune reaction was evidenced by immunohistochemistry in the cytoplasm of approximately 10% of the pituitary cells with a density of 8.5 ± 1.9 (per 0.01 mm(2)), both periodic acid-Schiff positive (30%) and negative (70%). All CB1-immunoreactive cells were also immune reactive for estrogen receptor type 1. Ovariectomy, either alone or combined with estrogen priming, did not modify the relative abundances of pituitary CB1 mRNA, but decreased (P < 0.01) the expression of estrogen receptor type 1 mRNA. Treatment with CB1 antagonist (rimonabant) inhibited (P < 0.01) LH secretory capacity by the pituitary after GnRH injection, and estrogen priming had no effect. The present findings indicate that the endocannabinoid system is a potential candidate for the regulation of the hypothalamic-pituitary-ovarian axis in reflex ovulatory species.
authors.affiliation: Sezione di Anatomia, Dipartimento di Scienze biopatologiche veterinarie, Università di Perugia, Via S. Costanzo 4, 06126 Perugia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Dall'Aglio
authors.forename: P
authors.initials: P
authors.lastname: Millán
authors.forename: M
authors.initials: M
authors.lastname: Maranesi
authors.forename: P G
authors.initials: PG
authors.lastname: Rebollar
authors.forename: G
authors.initials: G
authors.lastname: Brecchia
authors.forename: M
authors.initials: M
authors.lastname: Zerani
authors.forename: A
authors.initials: A
authors.lastname: Gobbetti
authors.forename: G
authors.initials: G
authors.lastname: Gonzalez-Mariscal
authors.forename: C
authors.initials: C
authors.lastname: Boiti
mesh_terms: D000818:Animals; D063387:Cannabinoid Receptor Antagonists / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000032:analysis / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D010052:Ovariectomy; D010880:Piperidines / Q000494:pharmacology; D010902:Pituitary Gland / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D011720:Pyrazoles / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits / Q000502:physiology*; D043884:Receptor, Cannabinoid, CB1 / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D000077285:Rimonabant
chemical_list: D063387:Cannabinoid Receptor Antagonists; C543264:Cnr1 protein, rat; D047628:Estrogen Receptor alpha; D004967:Estrogens; D010880:Piperidines; D011720:Pyrazoles; D012333:RNA, Messenger; D043884:Receptor, Cannabinoid, CB1; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D000077285:Rimonabant
keywords: CB1; Endocannabinoids; LH; Rabbit; Rimonabant